IMHO, I believe, HackerNews is a place for intellectual discussions related to hacking culture and I think a good and respected Sci-Fi writers obituary is a perfect but sad opportunity for starting great discussions.

So if you look into HN Faq Question 1's answer:

"On-Topic: Anything that good hackers would find interesting. That includes more than hacking and startups. If you had to reduce it to a sentence, the answer might be: anything that gratifies one's intellectual curiosity. "

Yes Pohl's obituary gratifies my intellectual curiosity.

Sure. If you want to find out whether one of those people is relevant to other hackers, then try posting the obit here. If it gets upvoted to the front page, then you'll know the answer is yes.